Gorilla skull

Gorillas are the largest living primates. Males grow considerably
larger than females.

The brain size of gorillas averages 500 cc, but males, being bigger,
tend to have larger brains than females. Various sources list the
maximum brain size of gorillas as 650 cc, 700 cc, or in the case of one
exceptional specimen, 752 cc (Tobias, 1964).

Skulls of male gorillas therefore overlap the skulls of Homo habilis
in brain size, but this is largely because they are far bigger than any
fossil hominid. When a correction is made for their huge body size,
gorilla brains are the same size as, or a bit smaller than, those of chimpanzees. In addition, male gorilla
skulls have a very different appearance from those of Homo fossils.
They have prominent crests and ridges of bone, while Homo habilis
skulls have little or no crests, and are much more rounded.

References

Tobias P.V. (1964): The Olduvai bed I hominine with special reference to
its cranial capacity. Nature, 202:3-4.